Some undersea creatures.
Sea Delver
Huge Aberration (Aquatic)
HD: 15d8+75
Initiative: +5
Speed: 15ft., Burrow 10ft., Swim 60 ft.
AC: 14 (-2 size, +1 dex, +5 natural) Touch 9, Flat-footed 13
Base attacks/Grapple: +11/+17
Attack: 2 Slams at +18 melee (1d6+8, 2d6 acid)
Full Attack: 2 Slams at +18 melee (1d6+8, 2d6 acid)
Space/reach: 15ft./15ft.
Special attacks: Acid
Special qualities: Acid immunity, Corrosive slime, Tremor sense, stone shape, Breathe water, Lowlight vision, water born.
Saves: Fort +10, Refl +6, Will +11
Abilities: Str 27, Dex 13, Con 21, Int 14, Wis 14, Cha 12
Skills: Survival +9, Swim + 17, Listen +15, Move silently +19, Spot +11
Feats: Alertness, blind fight, Improved initiative, power attack
Environment: The submerged reaches of the Underdark
Organization: Solitary
Challenge rating: 9
Treasure: none
Alignment: Usually Neutral
Advancement: 16-30 HD (Huge); 31-45 HD (Gargantuan)
After thousands of years of living in the deep recesses of the Underdark, a few delvers reached the sea, and finally adapted to it. They gained gills along the side of the head, there claw already acting as flippers weren’t changed. Instead of swimming though they moved along the sea bed, like hippopotami.
Combat:
Not much has changed with the tactics and style of Sea delver combat.
Corrosive Slime (Ex): Sea delvers produce a highly corrosive, mucus like slime. This is extremely effective against stone. A sea delver’s mere touch deals 2d6 acid damage to objects and organic creatures, it deals 4d8 damage against metallic creatures or objects, but against stone based creatures and objects it deals 8d10 damage. On a successful slam attack it delivers a patch of slime that delivers the acid damage immediately, and then again over two rounds. You can neutralize it with at least a quart of soap, or other alkalis. An opponents armour and clothing become useless immediately, unless a reflex save of 22 is made, if the armour is magical you add the enhancement to the save. Weapons dissolve instantly unless the wielder makes a reflex DC of 22, with the weapons enhancement bonus added to the roll.
Tremorsense (Ex): A sea delver can sense the location of anything in contact of the ground, within 60ft.
Stone shape (Ex): The sea delver can temporarily change the slime it produces from dissolving stone to softening it. This performs much like a stone shape spell cast by a 15th level druid, covering 25 cubic feet.
I haven't finished this completly:
Sea monkeys (Aquatic, Reptilian)
Tiny Animal
Hit Dice: 1d8+1 (5 hp)
Initiative: +2
Speed: 15 ft. (6 squares), climb 15 ft. Swim 60ft. (10 squares)
Armour Class: 16 (+2 size, +2 Dex +2 natural), touch 14, flat-footed 14
Base Attack/Grapple: +1/–11
Attack: Bite +4 melee (1d3–3) OR Claw +4 melee (1d3-3)
Full Attack: Bite +4 melee (1d3–3) OR Claw +4 melee (1d3-3)
Space/Reach: 2-1/2 ft./0 ft.
Special Attacks: —
Special Qualities: Low-light vision, Scent, Water born
Saves: Fort +3, Ref +5, Will +1
Abilities: Str 5, Dex 15, Con 12, Int 2, Wis 14, Cha 5
Skills: Balance + 14, Climb +10, Hide +10, Listen +1, Jump +4 Spot +5
Feats: Weapon Finesse
Environment: Warm forests
Organization: Troop (10–40)
Challenge Rating: 1
Advancement: 2–3 HD (Small)
Level Adjustment: —
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Combat
Sea Monkeys generally flee into the safety of kelp, but if cornered can fight ferociously.
Waterborn (Ex): Waterborn creatures are at a general -1 penalty out of water.
Skills: Monkeys have a +12 racial bonus on Balance, + 8 Climb, a +4 bonus on jump checks, -2 on listen, +2 on spot and +8 on swim. They can always choose to take 10 on Climb checks, even if rushed or threatened. They use their Dexterity modifier instead of their Strength modifier for Climb checks